Aramid fibers are highly resistant to heat decomposition, have inherent flame-resistant properties, and are frequently used in working wear for special environments where flame resistant properties are required. Fabrics made of these fibers are extremely strong and durable, and have been widely adopted for military applications where personnel have the potential to be exposed to fire and flame, such as aircraft pilots, tank crews and the like. There is a need for fabrics that have flame-resistant properties that are able to successfully meet even higher performance requirements. Meta-linked aromatic polyamide fibers (aramid fibers) are made from high molecular weight polymers that are highly crystalline and have either a high or no glass transition temperature.
These inherent desirable properties of aramid fibers also create difficulties for fiber processing in other areas; specifically, aramids are difficult to dye and difficult to finish so as to enhance their durable flame-resistant properties.
It is an object of the present invention to provide a process for improving the flame-resistant properties of an aromatic polyamide fiber that will yield an increase in flame-resistance without detracting from the inherent strength of the aramid fibers.